Lunar landing depends on the selection and identification of an appropriate location that is level and free of hazards, along with a stable, controlled descent to the surface. During crewed landings, astronauts are expected to interact with automated systems, based upon improved terrain maps and sensor updates, to perform tasks such as manual re-designation of landing point, adjustment of descent trajectory or direct manual control. However, sensorimotor limitations, both vestibular and visual, are likely to interfere with performance and safety. This integrated project examines the nature of the anticipated spatial disorientation and terrain perception limits as they affect the transition from automatic to manual control and develops advanced display countermeasures to overcome these limitations.

There are four specific aims investigated in this multi-institution effort:

1. Examine the nature of anticipated sensorimotor difficulties (e.g., spatial disorientation, limits on terrain perception) as they affect the transition from automatic to manual control;

2. Develop and evaluate advanced display countermeasures for enhancing situation and terrain awareness and for overcoming performance limitations caused by reduced visibility associated with lunar lighting, terrain reflectivity and the absence of atmosphere utilizing Draper Laboratory's fixed-base lunar lander cockpit simulator for full human-in-the-loop evaluation;

3. Evaluate the effectiveness of the cockpit displays during human-in-the-loop manual control in the NASA Johnson Space Center (JSC) Tilt-Translation Sled (TTS) during "critical" and "hover" tasks testing the tilt-translation and tilt-gain illusions of altered acceleration sensitivity as it applies to lunar gravity following a period of weightlessness; and

4. Perform a series of evaluations of the displays using the U.S. Army Aeromedical Research Laboratorys six-degree-of-freedom helicopter simulator as a lunar landing analog for replicating lunar lighting and the various parameters associated with dust "brownout" conditions.

Following this review, we have begun developing the first set of prototype cockpit displays and controls for the Draper simulator. These displays are focused on the final hover and descent tasks, providing information on lander attitude, fuel usage and geographical awareness. The first displays have also been tested in a simple MATLAB/Simulink environment and will soon be ready to integrate into the full simulation. The team visited JSC to review Dr. Wood's TTS and discuss the integration of the Draper hardware and software into the TTS. The hardware and software interfaces have been determined, and we are now in the process of finalizing the equipment to achieve some commonality between Draper and JSC simulations. The Aim 3 experiment protocol will be ready for submission to the JSC Institutional Review Board (IRB) by the end of May. The groundwork for the Aim 4 experiments, which are not scheduled until Years 3-4, is being started as the US Army will be modifying their 6-DOF helicopter simulation to allow changes in the dust simulation. This will enable us to alter dust properties to match those of lunar regolith.

For the second year, we will continue our work on Aim 1, examining the effects of lighting and dust on spatial orientation and manual control during landing. For Aim 2, we will finish the development of a set of prototype cockpit displays for the Draper simulator. Experiments using these displays to land on the lunar surface will be carried out in the Draper simulator. Flight and landing performance, situation awareness and pilot workload will be evaluated. We will update the landing trajectory analysis and display experiments as more information about the flight dynamics of the actual Altair vehicle are released. In the summer of 2009, after JSC IRB approval, we will complete the installation of the Draper hardware and software into the JSC TTS. Once complete, we will begin a pilot experiment to verify that tilt-translation illusions can be generated with the system. The main experiment examining the effect of sensory discord on landing performance will be carried out as described in the proposal. We anticipate that work on the US Army Aerospace Research Lab simulator will begin and be completed in Year 2.

Earth-based Applications of Research Project
Human rating requirements currently mandate the capability for a "graceful reversion" from automated to manual control for spaceflight control systems. Our goal is to determine the limits of human performance under likely landing conditions that may cause spatial disorientation. Appropriate roles can thereby be selected for humans and automated systems. This proposed project will contribute to a better understanding of visual and vestibular conditions contributing to spatial disorientation during landing and the resulting effects on human manual control. We will have demonstrated display and control system interfaces to reduce pilot workload, improve situation awareness and mitigate spatial disorientation to ensure a safe crewed lunar landing. Finally, the work may also have terrestrial applications in mitigating the risk of helicopter accidents by suggesting new techniques to address problems associated with brownout during landing.

Project Description
NASA Task Book Entry